Macewka



2 Sheets-Sheet 1 Original Filed larch 7. 1951 W m H 3 m c N V A w mM 2 WN 4 M EJ 6% Y B N 2 NM 2 9L q n lduH u HHMH Nov. 2, 1954 J. MACEWKA Re.23,

FLUID ACTUATED PRESS Origin a1 Filed llafch 7, 1951 2 Sheets-Sheet 2 INV EN TOR. JoH/v M4 05 WAA fim Zi ATTOPNEV FLUID ACTUA'I'ED PRESS JohnMacewlta, Detroit, Mich.

Original No. 2,642,138, dated June 16, 1953, Serial No. 214,398, March7, 1951. Application for reissue June 3, 1954, Serial No. 434,354

7 Claims- (Cl. 164-95) Matter enclosed in heavy brackets I: II appearsin the original patent but forms no rt of this reissue specification;matter printed in italics dicntes the additions made by reissue Thepresent invention relates to an hydraulically actuated press and moreparticularly to such a press including an assembly of hydraulic pistonsadapted to actuate a press tool and the accompanying stripper plate inproper sequence. This application is related to my co-pendingapplication, Serial No. l 14,022, filed September 3, 1949, entitledHydraulic Cylinder."

It is well known that press constructions embody a pressure plate orother means for holding a workpiece in position for the press operation,and also a stripper plate which will separate the finished workpiecefrom the press tool after the press operation is completed. The stripperplate and pressure plate are often com; bined into one element known asthe stripper clamp. The stripper clamp is placed upon the workpieceunder pressure to hold the workpiece in position, the press operation isperformed, and the stripper clamp is ma ntained on the workpiece to holdit in position while the press tool is removed from the workpiece.

Conventional press constructions us ng this stripper clamp havegenerally utilized a complicated system of hydraulic circuits to effectthe necessary operations, such systems embracing an excessively largespace. Factory space is extremely valuable and plant layout engineersare ever attempting to utilize every bit of area to its best advantage.Thus, an efficient hydraulic press construction has been sought which issimple, easy to maintain, and compact.

Another disadvantage of conventional construction has been the necessityof providing a large number of heavy, closely machined ways or guides onthe stripper clamps so that such guides will accurately seat thestripper clamps, and withstand the pressures to which they areSllbjCCtCd. Therefore, stripper clamp constructions which are efficient,and which have an accurate, simple, and sturdy guiding means have longbeen desired. I

It is, accordingly, a primary object of the present invention to providea simple and efficient hydraulic press construction embodying a stripperclamp-and a press mechanism cooperating therewith, which are actuated inproper sequence by a simple and compact hydraulic unit.

It is a further object of the present invention to provide a pressconstruction embodying a stripper clamp which has simple and efiicientsupporting and guiding means.

It is a further object of the present invention to provide an hydraulicpress employing a plurality of hydraulic cylinders so disposed andarranged with respect to the press tool and stripper clamp that thestripper clamp and press tool will move relative to each other toprovide the necessary holding, working, and stripping operations.

It is another object of the present invention to provide an hydraulicpress including a main piston rigidly and transversely connected with aplurality of supplemental pistons, said main piston being connected tothe press tool at its free end, and each supplemental piston having asecondary piston in limited sliding engagement therewith, said secondarypistons being rigidly aflixed to a stripper clamp to efiect relativemovement between the press tool and the stripper clamp.

Other objects of this invention will appear in the following descriptionand appended claims, reference 4 United States Patent Re. 23,892 ReiuuedNov. 2, 1954 Fig. 1 is a midsection of an hydraulic press embodying onemodification of the present invention, with portions of the pistons andstripper clamp being broken away for its clarity.

Fig. 2 is a sectional view taken along the line 2--2 in the direction ofthe arrows Fig. 1.

Fig. 3 is a side view of an hydraulic press embodying anothermodification of the present invention, with portions broken away todisclose the internal construction. F Fl 4 is an end view of theembodiment shown in I Before explaining the present invention in detail,it s to be understood that the invention is not limited in itsapplication to the details of construction and arrangement of partsillustrated in the accompanying drawings, since the invention is capableof other embodiments and of being practiced or carried out in variousways.v Also, it is to be understood that the phraseology or terminologyemployed herein is for the purpose of description and not of limitation.

Referring to the modification of the present invention shown m Figs. 1and 2 of the drawings, an hydraulic press is shown comprising thehousing 10 having the cylinders 12, 14, and 16 formed therein. The mainp ston 20, and the supplemental pistons 18 and 22 are disposed in thecylinders 12, 14, and 16 respectively. An elongated slot 23 is formed inthe housing 10 and connects the cylinders 12, 14, and 16. A dowel member24 is disposed in the slot 23 and rigidly connects the pistons 18, 20and 22. Suitable piston rings or seals 25 are provided on each of thepistons 18, 20, and 22 to prevent the hydraulic fluid from leakingaround the piston walls.

The ends of the housing 10 are closed by the end plates 26and 28. Theslot 23, which extends through the outer side walls of the housing 10,is closed by the side plates 34 and 36 respectively.

The main piston 20 has the press tool 38, in this instance a punch,atiixed to its free end. The tops of the supplemental pistons 18 and 22are provided with the hollow interiors 40 and 42. The interiors of thesetwo piston constructions are identical and the remarks in connectionwith the supplemental piston 18 will also apply to the supplementalpiston 22. The foot of the supplemental piston 18 is provided with thesecondary cylinder portion 44 having disposed therein a secondary piston46. A suitable piston ring or seal is indicated at 47. The secondarypiston 46 is provided along its side with the elongated slot 48.Disposed within this slot 48 is the pin 50 which is rigidly affixed tothe supplemental piston 18. The free end of the secondary piston 46comprises the guide rod 52. The corresponding parts in the supplementalpiston 22 are the secondary piston 53, the slot 54, the pin 56, and theguide rod 58. The guide rods 52 and 58 are connected by any suitablemeans such as the bolt 60 to the stripper clamp 62. The stripper clamp62 in this instance is provided with the holes 64 and 66 to accommodatethe punches 68 and 70 on the press tool 38. Conduits 72 and 74 areprovided in the body of the supplemental piston 18 and connect thatchamber 40 with the cylinder 44. Similar conduits 76 and 78 are providedin the body of the supplemental piston 22.

Ports 80, 82, and 84 are provided in the housing 10 to adapt the housing10 for connection with an hydraulic circuit. These ports arescrew-threaded to facilitate connection with the screw-threadedconnecting caps which are provided on hydraulic hoses. Mounting holes86, 88, and 92 are provided in the housing 10 to adapt the housing formounting on a press frame. Passages 94 and 96 are provided at the leftend of the housing 10 (Fig. 1) to connect the cylinders 12, 14, and 16.Suitable bearings 98 and 100 are disposed at one end of the housing 10adjacent the end plate 28. These bearings guide and support the rods 52and 58. Seals 102 and 104 are provided in the bearings 98 and 100 toprevent leakage of hydrau i uid through the end plate 28.

3 OPERATION The operation of the modification shown in Figs. 1 and 2 ofthe drawings is as follows:

Hydraulic fluid is introduced through the port 84 against the top of thepiston 20 and passes through passages 94 and 96 into the cylinders 14and 16. The hydraulic fluid passes into the chamber 40 in thesupplemental piston 18 through the conduits 72 and 74, into thesecondary cylinder chamber 44 and against the top of the secondarypiston 46. The same action takes place in connection with thesupplemental piston 22. The secondary pistons 46 and 53 are forced tothe right relative to the pins 50 and 56 and thus, the stripper clamp 62precedes the press tool 38 in operative travel. The workpiece is firstengaged by the stripper clamp 62 and then the press tool 38 followsthrough to perform the punching operation,

the pins 50 and 56 moving within the slots 48 and 54, respectively. Whenthe operation is completed, the hydraulie fluid is introducedthrough theports 80 and 82 into the bottom of the cylinders 18 and 22. At thispoint, the pins 50 and 56 are near the right end of the slots 48 and 54.As fluid is introduced through the ports 80 and 82 the pressure withinthe bottom of supplemental cylinders 14 and 16 is increased to a pointwhere it is greater than the pressure being exerted within the chambers40 and 42 in the heads of the supplemental pistons 18 and 22. Thus, thesupplemental pistons 18 and 22 are moved leftward against the fluidpressure n the top of the supplemental cylinders 14 and 16 and in thechambers 40 and 42. As the supplemental pistons 18 and 22 move leftward,fluid from the chambers 40 and 42 moves through the conduits 72 and 74and maintains the pressure on the heads of the secondary pistons 52 and58, thereby holding the stripper clamp 62 in position on the workpiece.The supplemental pistons 18 and 22 thus move leftward until the pins 50and 56 contact the left walls of the slots 48 and 54 thus moving thepress tool 38 away from the workpiece while the stripper clamp 62 isheld thereon, and pulling the punches 68 and 70 through the openings 64and 66 in the stripper clamp 62. Thus, the supplemental pistons 18 and22 and the press tool 38 are moved leftward a distance approximately thelength of one of the slots 48 or 54 before the said supplemental pistonsstart to effect the leftward movement of the rods 52 and 58 and thestripper clamp 62 connected thereto. When the punches 68 and 70 havecleared the workpiece, the pins 50 and 56 have reached their leftwardlimit of travel in the slots 48 and 54, respectively, and the guide rods52 and 58 with the stripper plate 62 aflixed thereto are carriedleftward. Thus, the cycle is completed with a simple hydraulic unit andwith a simple and compact mechanism.

A modification of the device shown in Figs. 1 and 2 is demonstrated inFigs. 3 and 4 of the drawings. 'I he important difference in thisconstruction is the provision of the separate hydraulic feed line 200.This line is connected with the passage 202 in the lower piston 204which communicates with the cylinder chamber 206 and in which chamberthe secondary piston 208 is disposed. Thus, it will be seen that thepassage 202 in this modification is substituted for, and performs thesame function as, the passages 72, 74, 76 and 78, shown in Ifig. of thedrawings. The operation of this modification is similar to that shown inFigs. 1 and 2 of the drawings. The pistons 204 and 210 are of identicalconstruction and the supplemental piston 210 utilizes the hydraulic feedline 212.

Suitable seals,.such as the neoprene T seals 214 are provided on thevarious pistons to prevent leakage of the hydraulic fluid. In addition,a bearing 216 is provided at one end of the housing 218 adjacent the endplate 220 in each of the cylinders 222 and 224 to guide and support therods 226 and 228. A retaining ring 230 is disposed around the rod 228and contains suitable sealing means such as the neoprene U seal 232. Asimilar construction is positioned around the rod 226.

OPERATION In discussing the operation of the modification shown in Figs.3 and 4 of the drawings, the operation of only one of the supplementalpistons, the supplemental piston 204 will be described. However, it isto be understood that the supplemental piston 210 and its accompanyingconstruction operate in an identical manner.

In operation, hydraulic fluid is introduced through the feed line 200which moves the secondary piston 208 to the right relative to thesupplemental piston 204. In the meantime, hydraulic fluid is introducedthrough the inlet port 237 which fluid has started the rightward travelof the connected pistons 204, 210 and 238. The stripper clamp 240.reaches the workpiece first and holds it in place while the press tool242 follows through with its operation. Upon the return stroke,hydraulic fluid is introduced through the return hose 244 until thefluid pressure at the bottom of the supplemental cylinder 224 is greaterthan the fluid pressure at the top thereof. This uid pressure causes thesupplemental piston to move leftward against the fluid pressure exertedupon the top of the piston. Since there is no component of the fluidpressure acting to the left on the secondary piston, the secondarypiston will remain in position under pressure until the pin 234, whichis affixed to the supplemental piston 204, contacts the left wall of theslot 236. The press tool 242 is moved leftward while the stripper clamp240 remains in position. The stripper clamp, thus, holds the workpiecein place so that the press tool 242 may be removed without displacingand distorting the workpiece. As the pin 234 hits the left wall of theslot 236, the press tool 242 has been removed from contact with the workpiece and the secondary piston 208 is then carried leftward by the pin234 which is rigidly afi'txed to the supplemental piston 204. Thus, thestripper clamp 240 is moved awayfrom the workpiece and the workpiece maybe removed. The return line for the supplemental piston 210 isdesignated at 246.

It will be understood, of course, that upon the return stroke, thehydraulic fluid in the cylinder 224 and the secondary cylinder 206 isdispelled through the lines 237 and 200, respectively, so that theselines, which were originally feed lines, now become drain lines.

Each of the modifications illustrated herein embody the novel featuresof the present invention to provide a simple and efficient pressconstruction'utilizing a combination stripper and pressure plate in theform of a stripper clamp, a simple and compact hydraulic circuit, sturdyguide and support means for the stripper clamp, and a secondary pistonassembly which elfects relative movement between the press tool and thestripper clamp.

Having thus described my invention, I claim:

1. A fluid [An hydraulically] actuated press comprising a housing havinga plurality of parallel cylinder bores therein and also having anelongated slot therein extending in the direction of the axes of saidbores, said slot interconnecting said bores, a main piston disposed inone of said bores and adapted for connection with a press tool, asupplemental piston disposed in another of said bores and adapted forconnection a dowel member extending through said slot in said housingand rigidly connecting said main piston and said supplemental piston, asecondary piston disposed within the foot of said supplemental piston inlimited sliding engagement therewith so that said secondary piston maymove a limited distance relative to said supplemental piston, means for[hydraulically] actuating said secondary iston with a fluid, means forthereafter [hydraulically actuating said main and supplemental pistonswith a fluid, and return means for returning secondly said secondarypiston and first said main piston and supplemental pistons to theirinitial positions.

2. A fluid [An hydraulically] actuated press adapted to hold a workpiecein position, perform a work operation thereon with a press tool, andstrip said workpiece from said press tool, including a housing with amain cylinder and supplemental cylinders parallel to said main cylinderformed therein, a main piston disposed in said main cylinder, a presstool connected to the free end of said main piston, a plurality ofsupplemental pistons disposed one in each of said supplemental cylindersand rigidly connected to said main piston so that main piston andsupplemental pistons will move together, each of said supplementalpistons having a secondary cylinder formed therein, a plurality ofsecondary pistons disposed one in limited sliding engagement with eachof said supplemental pistons in the secondary cylinder formed therein, astripper clamp attached to the free ends of said secondary pistons, anda fluid supply [an hydraulic] system including means to feed said main,supplemental, and secondary cylinders so that said secondary pistonswill move relative to said supplemental pistons to effect the necessaryholding and stripping operations.

to a stripper clamp,

3. [An hydraulically] A fluid actuated press comprising a housing havinga plurality of parallel cylinder bores therein and also having anelongated slot therein extending in the direction or the axes of saidbores, said slot interconnecting said bores, a main piston disposed inone ofsaid cylinder bores and adapted for connection with a press tool,a plurality of supplemental pistons disposed one in each of the other ofsaid bores, each of said supplemental pistons having an open chamberformed in the head thereof and a secondary open cylinder formed at thefoot thereof which are connected by a passage, a dowel member extendingthrough said housing slot and rigidly connecting said main andsupplemental pistons together, a plurality of secondary pistons disposedone in each of the secondary cylinders in said supplemental pistons andhaving an elongated slot therethrough extending in the direction of itsaxis, a pin rigidly aflixed to said supplemental piston and extendingthrough said slot, a con necting rod extending from the free end of saidsecondary piston and adapted for connection to a stripper clamp, inletmeans communicating with the head or said main and supplementalcylinders and adapted to first actuate said secondary pistons througnthe passages in said supplemental pistons until the side wall of theslot in said secondary piston contacts the pin and moves thesupplemental piston, and then moves said main and supplemental pistons,return means communicating with the other end of each of saidsupplemental cylinders and adapted to move said supplemental pistons inthe return stroke until the pins aflixed thereto contact the side wallsof the slots in said secondary pistons at which time the secondarypistons also move, and a source of [hydraulic] fluid connected with saidinlet and return means.

4. [An hydraulically] A fluid actuated press comprising a housing havinga plurality of parallel cylinder bores therein and also having anelongated slot therein extending in the direction of the axes of saidbores, said slot interconnecting said bores and extending through atleast one external side wall of said housing, a main piston disposed inone of said cylinder bores and adapted for connection to a press tool, aplurality of supplemental pistons disposed one in each of the other ofsaid bores, a dowel member extending through said housing slot andrigidly connecting said main piston and said supplemental pistonstogether, a secondary open cylinder formed at the foot of each of saidsupplemental pistons, a secondary piston disposed in each of thesecondary cylinders in said supplemental pistons and having an elongatedslot therethrough extending in the direction of its axis, a pin rigidlyalfixed to said supplemental piston and extending through said slot, aconnecting rod extending from the free end of said secondary piston andadapted for connection to a stripper clamp, a passage extending from theside of at least one of said supplemental pistons and communicating withthe secondary cylinder formed therein, inlet means connected to theopening of the passage in the side of said supplemental piston andextending through the slot in the external side wall of said housing,inlet means communicating with the head of the main and supplementalcylinders, and return means communicating with the foot of at least oneof said supplemental cylinders, all of said inlet means and return meansbeing adapted for connection to a source of [hydraulic] fluid underpressure.

5. A fluid [An hydraulically] actuated press adapted to hold aworkpiece, perform a work operation thereon with a press tool, and stripsaid workpiece from said press tool comprising a housing having aplurality of cylinder bores therein, a main piston disposed in one ofsaid cylinder bores, a press tool afilxed to the free end of said mainiston, a supplemental iston disposed in another 0 said cylinder bores anhaving a secondary cylinder formed therein, said main piston andsupplemental piston being directly connected to move togeuler, asecondary piston disposed in limited sliding engagement with saidsupplemental piston in the secondary cylinder formed therein, a stripperclamp aflixed to the free end of said secondary piston, and [hydraulic]means for feeding fluid to said main, supplemental and secondarycylinders so that said secondary pistons will move relative to saidsupplemental pistons to efiect the necessary holding and strippingoperations.

6. A fluid [An hydraulically] actuated press comprising a housing havinga plurality of cylinder bores therein, a main piston disposed in one ofsaid cylinder bores and adapted for connection with a press tool, asupplemental piston disposed in another of said bores and rigidlyaffixed to said main piston for movement therewith, said supplementalpiston having an open chamber formed in the head thereof and a secondarycylinder formed at the foot thereof which are connected by a passage, asecondary piston disposed in said secondary cylinder and having anelongated slot therethrough extending in the direction of its axis, apin rigidly affixed to said supplemental piston and extending throughsaid slot, a connecting rod extending from the free end of saidsecondary piston and adapted for connection to a stripper clamp, inletmeans communicating with the head of said main and supplementalcylinders and adapted to first actuate said secondary piston through thepassage in said supplemental piston until the side wall of the slot insaid secondary piston contacts the pin and moves the supplementalpiston, and then moves said main and supplemental pistons, return meanscommunicating with the other end of said supplemental cylinder andadapted to move said supplemental piston in the return stroke until thepin affixed thereto contacts the side wall of the slot in said secondarypiston at which time the secondary piston also moves, and a source of[hydraulic] fluid connected with said inlet and return means.

7. A fluid [An hydraulically] actuated press comprising a housing havinga plurality of parallel cylinder bores therein and also having anelongated slot extending through an external side wall thereof in thedirection of the axes of said bores, a main piston disposed in one ofsaid cylinder bores and adapted for connection to a !press tool, a suplemental piston disposed in another .0 said bores an rigidly aflixed tosaid main iston for movement therewith, said supplemental piston havinga secondary cylinder formed at the foot thereof, a secondary pistondisposed in said secondary cylinder and having an elongated slottherethrough extendin in the direction of its axis, a pin rigidlyafiixed to said supplemental piston and extending through said slot, aconnecting rod extending from the free end of said secondary piston andadapted for connection to a stripper clamp, a passage extending from theside of said supplemental piston and communicating with the secondarycylinder formed therein. inlet means connected to the opening of thepassage in the side of said supplemental piston and extending throughthe slot in the external side wall of said housing, inlet meanscommunicating with the head of the main and supplemental cylinders. andreturn means communicating with the foot of said supplemental cylinder,all of said inlet means and return means being adapted for connection toa source of [hydraulic] fluid under pressure.

References Cited in the file of this patent or the original patentUNITED STATES PATENTS Name Dat mber 2, 18,648

